Integrated mica and method of making the same



Aug. 13, 1946.- M. D. HEYMAN INTEGRATED MICA AND METHOD OF MAKING THE SAME Filed June 3, 1945 IN VEN TOR.

M0555 0 HHM/w f ATTORNEY Patented Au.13,-1946 t INTEGRATED MICA AND METHOD F MAKING THE SAME Moses D. Herman, Cedarhurst, N. Y., assigner,

by mesne assignments. to Integrated Mica Corporation, Woodmere, N. Y., a corporation of New York Application June 3, 1943, Serial No. 489,478

11 Claims. (Cl. 12S-24) This invention relates to the forming of mica sheets from either blocks or particles of mica, and has for its primary object the manufacture of sheets of mica of indefinite size without the use of any binder, so that the resultant product is truly a sheet of pure mica.

In this way, the sheet of mica will have substantially all of the desirable properties of original mica, which is only found in its natural state in relatively small crystals.

In order to make larger sheets, mica is usually split into thin layers and put together under heat and pressure, using a binder such as shellac, copal,

varnish, etc. However, the presence of these binders deleteriously affects many of the original properties of the mica, such as its resistance to `heat and its electrical properties, such as its power factor, etc.

By means of the present process, mica, which can be mica scrap, is separated into lamina and then replaced in contiguous relation, without the use of a binder, so that a. pure mica, sheet is obtained..

Through years of research and experiment the applicant has found that when a piece of mica is split and then is pressed together again quickly, the splittings wil1 recohere with substantially the same force as held them together before they` were split apart. This was found particularly true of very thin splittngs. When a piece of mica is split, there are presented two virgin surfaces. However, if these surfaces should be touched by a iinger or any other substance, such as a knife, or if they should be exposed to the open air for any length of time, they can n0 longer be made to recohere. No amount of cleansing the surfaces will reestablish the coherlng force. It follows then that if mica can be split apart without marrng or contaminating the surfaces in any shape or form, the thin layers can once more be put together and will form a perfect mica sheet. The following sets forth the prime requisites for making integrated mica:

First: The surfaces of the mica splittings must be virgin.

Second: 'I'he splittings must not be permitted to be contaminated.

Third: The mica when split must be very thin, preferably to a thickness of M0000 of an inch or less.

As` a result of the research on the primary facts as herein stated, the applicant has conceived a method of fabricating mica as further described and as shown in a semi-diagrammatic manner in the accompanying drawing.

In the drawing:

Fig. 1 is a flow diagram showing the means for fabricating mica sheets in accordance with the invention.

Fig. 2 is a plan view of such a sheet.

Fig. 3 is an enlarged cross-sectional view as taken on the line 3--3 of Fig. 2.

Describing the invention in greater detail, a quantity of mica blocks of varying size and thickness, or even mica scrap, is subjected to the cleansing action of Water or other fluids. The cleansing may be accomplished in more than one stage, if desired, to rid the imica. of dirt, stones or any other impurities. The cleansed mica may then be dried in drying ovens to rid the pieces of all moisture. Having been thus cleansed, the mica is preferably fed to a splitting device I0, which is shown in its present preferred form. This splitter preferably comprises a casing II, having a hollowed-out portion which is shaped like a figure eight. Thus the casing II may be provided respectively with lower and upper chamhers I 2 and I 3 and a communicating restricted opening I4, formed by at least one in-reaching wall I5 of the casing. This wall should preferably come to a substantially sharp edge so that when a stream of liquid under high pressure strikes the edge it will be divided, the parts of the stream moving in the direction of the arrows. In this manner, the stream of liquid wil more or less follow the contour of the gure eight. There will then be a crossing of currents at the restricted opening I4 when the liquid from the right hand wall of the upper chamber cuts across the stream from the lower chamber. The high pressure liquid from the stream leaving the high pressure nozzle I6 will further cause a continuous turbulence at this point.

The liquid preferred to be used as the liquid medium in the splitter is methyl alcohol, although it has been found that distilled water which has had the air driven therefrom is also quite effective.

In actual operation, mica will be dropped' into the liquid and will rest at the bottom of chamber I2. The action of jet I6 will be such as to divide the stream at the edge I5 and this action will carry the mica, around in a counter-clockwise manner. The natural path of the mica will be from the bottom of chamber I2 around the right hand side of said chamber. The mica will then have a tendency to follow the left hand side of the upper chamber Il. However, when a piece of mica approaches the restricted opening, it will strike the turmoil of cross currents which will twist and twirl the piece of mica around and the jet I6 will have many opportunities to strike the edge of the mica, thus splitting it. The mica will then pass around the contour of wall I5. The velocity of the mica piece after being struck by the jet IS will be high, but 'the velocity of the .liquid in chamber i2 or I3'wili be much lower. This will again have a further tendency to split the mica. After passing around the contour of chamber I3, the mica piece will once mare come within the path of the',jet I6 and will again be twisted and tniried by* the eddy-current set up in the restricted opening. Therefore, it will once more be split and sent int'o chamber I5. This process will continue until the particles of mica. are so thin that they will eventually oat up into the vented outlet |1- and thence to the opening I8.

A pervious member 20 is provided upon which the thin mica flakes are deposited and they are built thereon into a sheet of desired thickness. When the built-up sheet 2l is removed from im mersion in the liquid, a stratified sheet structure has formed and thus the contiguous surfaces of lhe flakes or laminae, being uncontaminated, Will cohere and form an integrated sheet of mica. It is desirable that the liquid be expelled from between the laminae and this can be done by applying heat and pressure. The liquid after being filtered and distilled can be re-circulated.

The various devices necessary to. carry out the steps of the method may be readily provided by skilled persons and the degree .of iineness of the mica splittings may be achieved in either a single stage splitter, as described, or by providing one of multiple stages as is evident.

It is further understood that although methyl alcohol or distilled Water is at present preferred as the immersion medium,. other liquids may prove to be equally effective for the purpose.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. The method of forming mica sheets which consists in splitting mica into iine splittings in methyl alcohol and depositing said splittings while immersed in said methyl alcohol upon a pervious surface.

2. The herein-described method of splitting nica which consists in subjecting pieces of mica to a splitting force while said pieces are immersed in methyl alcohol.

3. The herein-described method of splitting mica which consists in placing pieces of mica in a fluid medium within a chamber, and applying a jet pressure upon said fluid and mica pieces to induce a circulation thereof whereby the pressure of the jet is directed upon said mica pieces to cause splitting thereof.

4. The herein-described method of splitting mica which consists in placing mica pieces in a chamber containing methyl alcohol, and applying a jet pressure upon said methyl alcohol and mica pieces to induce a circulation thereof whereby the pressure of the jet is directed upon said *nica pieces to cause the same to split.

5. The method of forming a sheet of mica which consists in cleansing pieces of mica t0 rid the same of impurities and foreign particles, freeing the mica pieces of moisture, splitting said pieces while they are immersed in a medium which obviates contamination of the surfaces of the mica splittings, and forming a stratified sheet of said splittings while they remain immersed in said medium.

6. The method of forming a sheet of mica which consists in cleansing pieces of mica to rid the same of impurities and foreign particles, freeing the mica pieces of moisture, splitting said pieces while they are immersed in a medium which obviates contamination of the surfaces of the mica splittings, forming a stratified sheet of said splittings while they remain immersed in said medium, and subjecting said sheet to heat and pressure to hasten evaporation of the immersing medium.

7. The method of forming a sheet of mica which consists in cleansing pieces of mica to rid the same of impurities and foreign particles, freeing the mica pieces of moisture, splitting said pieces while they are immersed in methyl alcohol, and forming a stratified sheet of said splittings while they remain immersed in said methyl a1- cohol.

8. The method of forming a sheet of mica which consists in cleansing pieces of mica to rid the same of impurities and foreign particles, freeing the mica, pieces of moisture, splitting said pieces While they are immersed in methyl alcohol, forming a stratified sheet of said splittings while they remain immersed in said methyl alcohol,

and subjecting said sheet to heat and pressure to hasten evaporation of the immersing medium.

9. A fabricated laminated mica sheet comprising extremely thin laminae having virgin surfaces, said laminae being arranged in random fashion whereby their surfaces are in contiguous relation and enabling the natural cohesive forces resident in the laminae to become effective, and whereby the laminated sheet differs from a natural mica sheet in that the laminae are relatively smaller and frequently lie in more than one plane.

10. The method of forming mica sheets which consists in separating the laminae of a natural mica sheet into fine splittings in a liquid medium whereby the virginity of the surfaces of said splittings is retained to retain the natural cohesive forces of the mica splittings, and depositing said splittings upon a pervious surface while immersed in said liquid medium.

1l. The method of fabricating mica sheets which consists in subjecting pieces of mica to a splitting force while said mica pieces are immersed in a liquid medium whereby the virginity of the surfaces of the resulting mica splittings is retained to retain the natural cohesive forces of the mica pieces, and depositing said mica splittings upon a pervicus surface While said splittings remain immersed in said liquid medium.

MOSES D. HEYMAN. 

